VM: Avoid allocating strings when disassembling code.

runtime/vm/profiler.h

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_PROFILER_H_
 #define VM_PROFILER_H_
 
 #include "vm/allocation.h"
 #include "vm/bitfield.h"
 #include "vm/code_observers.h"
@@ skipping 416 matching lines @@
 
   uword Size() const;
 
   int64_t CompileTimestamp() const;
 
   RawCode* code() const {
     return code_.raw();
   }
 
   const char* Name() const {
-    const String& name = String::Handle(code_.Name());
-    return name.ToCString();
+    return code_.Name();
   }
 
   bool Contains(uword pc) const {
     uword end = Start() + Size();
     return (pc >= Start()) && (pc < end);
   }
 
   static int Compare(CodeDescriptor* const* a,
                      CodeDescriptor* const* b) {
     ASSERT(a != NULL);
@@ skipping 230 matching lines @@
  private:
   ZoneGrowableArray<ProcessedSample*> samples_;
   CodeLookupTable* code_lookup_table_;
 
   DISALLOW_COPY_AND_ASSIGN(ProcessedSampleBuffer);
 };
 
 }  // namespace dart
 
 #endif  // VM_PROFILER_H_